Lawyers for the defendants in the $5 million Fogg Museum coin robbery trial will appeal before the state Supreme Court today their allegation that the key prosecution witness in the 1973 robbery was beaten and coerced into testifying.

Earlier this week, Judge Herbert F. Travers Jr. of the Middlesex Superior Court denied a motion to dismiss charges or suppress evidence in the case because of the lawyers' contention.

Private Eye

The lawyers are basing their motion on the grounds that Harvard hired a private detective who allegedly beat and terrorized a man who later testified for the prosecution.

Travers told the Associated Press yesterday that Martin G. Regan's decision to cooperate with the prosecution was "free from all duress and coercion." Regan has reportedly been granted immunity from prosecution to turn state's evidence.

Daniel Steiner '54, general counsel to the University, said yesterday that, based on his knowledge of the case, Judge Travers' decision appeared correct. Steiner added that he has not yet read the judge's decision.

Irving Richards, the private detective Harvard hired to recover the coins, has been charged with assault and battery and breaking and entering with intent to commit larceny last month. The man he allegedly beat was Regan.

If the state court rejects the prosecution's motion today, the trial will probably begin Friday, Robert J. Barker II, assistant district attorney of Middlesex County, said yesterday.

In December, 1973, four men entered the Fogg Museum, overpowered the night guard and stole 5762 ancient Greek and Roman coins.

Three of the four people who allegedly participated in the robbery are now on trial. Anthony B. Vaglica, Louis R. Mathis and Carl R. LDison are charged with armed robbery and Maria T. Megna is charged with being an accessory after the fact